Rotational speed adjustment of axial flow fans to maximize net power output for direct dry cooling power generating units

Chen, Lei; Sun, Yen; Yang, Linlin; Du, Xiaoze; Yang, Yongping

doi:10.1002/htj.21616

Cited by 8 publications

(5 citation statements)

References 28 publications

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“…When the operating states of fans change, their characteristic parameters will vary accordingly. For a certain fan, the variations in the parameters obey the similarity principle as follows when only the rotational speed changes [33].…”

Section: Mathematical Models and Methodsmentioning

confidence: 99%

Cooling Performance Optimization of Direct Dry Cooling System Based on Partition Adjustment of Axial Flow Fans

et al. 2020

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Axial flow fans play key roles in the thermo-flow performance of direct dry cooling system under windy conditions, so the energy efficiency of a power generating unit can be improved by optimizing the operation strategies of the axial flow fans. In this work, various measures based on the partition adjustment of axial flow fans with constant power consumption of a 2 × 660 MW power plant are studied by computational fluid dynamics (CFD) methods. The results show that increasing the rotational speed of the windward fans is beneficial to reduce the inlet air temperature and increase the mass flow rates of the fans, which enhance the heat rejections of the air-cooled condensers, especially at high wind speeds. Moreover, the turbine back pressures for the optimal and original cases are achieved by iterative methods, with the largest drop of 2.77 kPa at the wind speed of 12 m/s for 110-case 3 in the wind direction of −90°. It is recommended to adopt 110-case 1 and 110-case 3 at low and high wind speeds, respectively, in the wind directions of 90° and −90°, while 110-case 2 is always the best choice in the 0° wind direction.

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Section: Mathematical Models and Methodsmentioning

confidence: 99%

Cooling Performance Optimization of Direct Dry Cooling System Based on Partition Adjustment of Axial Flow Fans

et al. 2020

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“…The windward surface of the computational domain was established as the velocity inlet boundary condition, the domain outlet was set as the pressure outlet boundary condition, and symmetric boundary conditions were adopted for the remaining surfaces when there was ambient wind. Equation (1) 22,23 was used to calculate the wind speed at a height above ground.…”

Section: Research Preparationmentioning

confidence: 99%

{v}_{i}={v}_{10}{\left(\frac{{z}_{i}}{10}\right)}^{m},

where v 10 (m/s) denotes wind speed at the height of 10 m. Any height, m , was denoted by z i (m); the ground roughness coefficient, m , which in this work was chosen to be 0.16; and the wind speed at z i was v i (m/s).…”

Section: Research Preparationmentioning

confidence: 99%

Operation optimization of cold‐end system of direct air‐cooled units considering the effect of environmental wind

Zhu¹,

Zhan²

2023

Heat Trans

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An air‐cooled island can significantly alter the heat transfer performance of an air‐cooled condenser due to the reflow of hot air caused by environmental wind. This can result in a considerable deviation between the backpressure calculated by traditional air‐cooled condenser models and the actual value. To address the issue, a research study was conducted on a 600‐MW direct air‐cooled unit. Numerical simulation methods were used to obtain the corresponding air flow rates and fan inlet air temperatures for each air‐cooled heat exchanger, which were then combined to establish a backpressure calculation model. From the above model, the backpressure prediction model and unit net output of full conditions were established using a backpropagation neural network. Therefore, taking the net output as the optimization objective, a genetic algorithm was used to compute the optimal backpressure and optimal fan speed in off‐design situations. Compared with traditional calculation approaches, the model produces backpressure predictions that were closer to the actual situation under the effect of ambient wind. The results indicate that both the optimal backpressure and fan speed were positively correlated with the exhaust flow and ambient temperature. It has been observed that when a unit was affected by different wind directions, the effect of the forwarding wind on the backpressure was smaller than that of other wind directions, especially under high‐load conditions. Moreover, the fan group operates close to full capacity under high‐temperature and high‐load conditions. Therefore, considering the influence of ambient wind, the obtained optimal backpressure and fan speed under variable working conditions were more realistic.

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“…Considering the dynamic variations within axial flow fan arrays, numerous researchers have directed their attention towards transitioning from the conventional unified control of fan groups to the par-titioned adjustment of axial flow fans. Chen [10] divided the 7 × 16 fan array into two zones and found that increasing the speed in the windward zone can significantly increase the output of the unit. In paper [11], for a 5 × 12 fan array, the fans are divided into six constituencies by column, and four speed strategies are designed.…”

Section: Introductionmentioning

confidence: 99%

Research on partition control of direct air‐cooling condenser based on multivariable Hammerstein CARMA model predictive control

Sun,

Deng,

et al. 2023

IET Control Theory & Appl

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Partition control of the fan array within a direct air‐cooling condenser (DACC) is recognized as a highly effective energy‐saving measure and a means to mitigate the adverse effects of ambient winds. This study focuses on the development of a dynamic partition model, which establishes the relationship between mass flow rate and fan array speed under windy conditions. The model is grounded in multivariable Hammerstein controlled autoregressive moving average (H‐CARMA) systems. Additionally, an innovative extended stochastic gradient algorithm, founded on the hierarchical identification principle, is introduced to estimate the model's unknown parameters. The recursive least square is employed as a benchmark to verify the accuracy and efficiency of the approach. Subsequently, leveraging the identified model, the model predictive controller based on the differential evolution method is designed to derive the optimal control law. Finally, simulation test and analysis are carried out to testify the effectiveness of our control strategy. The experiment result shows that the dynamic characteristics of the system have been significantly improved and the fan power consumption is reduced by 3.5% compared to the PID controller.

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Rotational speed adjustment of axial flow fans to maximize net power output for direct dry cooling power generating units

Cited by 8 publications

References 28 publications

Cooling Performance Optimization of Direct Dry Cooling System Based on Partition Adjustment of Axial Flow Fans

Cooling Performance Optimization of Direct Dry Cooling System Based on Partition Adjustment of Axial Flow Fans

Operation optimization of cold‐end system of direct air‐cooled units considering the effect of environmental wind

Research on partition control of direct air‐cooling condenser based on multivariable Hammerstein CARMA model predictive control

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